With the first three episodes of this superb American remake of BBC series Criminal Justice, we saw young student Nasir Khan tabbed for the murder of Andrea Cornish. Although he made some elementary, incriminating mistakes the moment he woke up from a drugs and alcohol bender that saw Cornish stabbed to death in the bedroom, his innocence has always been suggested, even though we don’t really know what happened. Ever since then, Naz has been plunged into a nightmare, tasked with surviving the harsh terrain of Rikers Island correctional facility, while both defence and prosecution prepare their cases for and against him on the outside.

NB: Spoilers ahoy

If anything, this series examines the predatory hierarchy of the US legal system. We’ve seen jail hustler John Stone nab his career-defining case and then have it cruelly snatched away from him by media-savvy, everything-savvy super-lawyer Alison Crowe. In episode four we saw her cast aside one of her employees – Chandra Kapoor – used principally for ethnicity in getting the Khan family onside. Crowe’s strategy for Naz to admit guilt and work out pleas bargain – manslaughter, with a 15-year stretch. That was her quick and easy route to another successful defence.

But she hadn’t reckoned on Naz himself, who was quickly changing inside Rikers. He was quickly having to learn how to survive, to adapt and to accept the news rules that now governed his life. He was toughening up; he had to.

So we saw a ruthless hierarchy on the outside, and a ruthless hierarchy on the inside. In both environments, cruelty reigned. It was a case of dog eat dog, where only the strong survived.

Everyone was telling Naz to take the plea bargain – Crowe, the people inside with him at Rikers, even John Stone, who was still taking an interest in the case. Instead, Naz decided to stick to his guns and once again pleaded innocence. The district attorney licked her lips; Alison Crowe dumped Naz in a fury and cast him off to Chandra, convinced that he was now if not a dead man walking, a certain lifer and a cross in the lost case column.

But Chandra did a smart thing. She went to John Stone, who had started to nose around to sate his own curiosity, and brought him back into the fold. Together they formed an unlikely partnership, but off they went to investigate further. It was irresistible viewing – the two of them edited in juxtaposition with wily old Box, both trying to find ways to either incriminate or defend. For Box he was tied to the office, poring through documents and CCTV footage, while Stone did what he did best – working the streets, chatting up the suspects, prizing information out of people like shucking an oyster. Slow, slow, bam! Open. It was the closest thing to a procedural since the first episode, and the pace of narrative upped noticeably. There was music, there was tension (the final scene when Stone went after Duane was electrifying) and there were things revealed.

Naz, meanwhile, had gone to Freddie for help, and soon the kingpin of Rikers had him under his wing. Naz shaved his hair, smoked dope in Freddie’s cell and began to take boxing lessons. He had taken brutal revenge on an inmate who had attacked him, and suddenly he was someone not to be messed with. Was this Naz just adapting and hardening himself while he was in prison? Or, as Freddie suggested, was there a hidden rage to Naz? Freddie’s protection, which provided its own rites of passage for Naz, was not without consequence – he had soon asked Naz to help smuggle in heroin, swallowing baggies to get them from the visiting room past security.

There was that hierarchy again. It was cruel and harsh, but the only way societies such as Rikers Island could exist. Naz had been prey on the outside, and now he was prey on the inside.